/* $Id: SetTopRule.java 467222 2006-10-24 03:17:11Z markt $
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.tomcat.util.digester;

import org.apache.tomcat.util.IntrospectionUtils;

/**
 * <p>
 * Rule implementation that calls a "set parent" method on the top (child)
 * object, passing the (top-1) (parent) object as an argument.
 * </p>
 * 
 * <p>
 * This rule now supports more flexible method matching by default. It is
 * possible that this may break (some) code written against release 1.1.1 or
 * earlier. See {@link #isExactMatch()} for more details.
 * </p>
 */

public class SetTopRule extends Rule {

	// ----------------------------------------------------------- Constructors

	/**
	 * Construct a "set parent" rule with the specified method name. The
	 * "set parent" method's argument type is assumed to be the class of the
	 * parent object.
	 * 
	 * @param digester
	 *            The associated Digester
	 * @param methodName
	 *            Method name of the "set parent" method to call
	 * 
	 * @deprecated The digester instance is now set in the
	 *             {@link Digester#addRule} method. Use
	 *             {@link #SetTopRule(String methodName)} instead.
	 */
	public SetTopRule(Digester digester, String methodName) {

		this(methodName);

	}

	/**
	 * Construct a "set parent" rule with the specified method name.
	 * 
	 * @param digester
	 *            The associated Digester
	 * @param methodName
	 *            Method name of the "set parent" method to call
	 * @param paramType
	 *            Java class of the "set parent" method's argument (if you wish
	 *            to use a primitive type, specify the corresonding Java wrapper
	 *            class instead, such as <code>java.lang.Boolean</code> for a
	 *            <code>boolean</code> parameter)
	 * 
	 * @deprecated The digester instance is now set in the
	 *             {@link Digester#addRule} method. Use
	 *             {@link #SetTopRule(String methodName, String paramType)}
	 *             instead.
	 */
	public SetTopRule(Digester digester, String methodName, String paramType) {

		this(methodName, paramType);

	}

	/**
	 * Construct a "set parent" rule with the specified method name. The
	 * "set parent" method's argument type is assumed to be the class of the
	 * parent object.
	 * 
	 * @param methodName
	 *            Method name of the "set parent" method to call
	 */
	public SetTopRule(String methodName) {

		this(methodName, null);

	}

	/**
	 * Construct a "set parent" rule with the specified method name.
	 * 
	 * @param methodName
	 *            Method name of the "set parent" method to call
	 * @param paramType
	 *            Java class of the "set parent" method's argument (if you wish
	 *            to use a primitive type, specify the corresonding Java wrapper
	 *            class instead, such as <code>java.lang.Boolean</code> for a
	 *            <code>boolean</code> parameter)
	 */
	public SetTopRule(String methodName, String paramType) {

		this.methodName = methodName;
		this.paramType = paramType;

	}

	// ----------------------------------------------------- Instance Variables

	/**
	 * The method name to call on the child object.
	 */
	protected String methodName = null;

	/**
	 * The Java class name of the parameter type expected by the method.
	 */
	protected String paramType = null;

	/**
	 * Should we use exact matching. Default is no.
	 */
	protected boolean useExactMatch = false;

	// --------------------------------------------------------- Public Methods

	/**
	 * <p>
	 * Is exact matching being used.
	 * </p>
	 * 
	 * <p>
	 * This rule uses <code>org.apache.commons.beanutils.MethodUtils</code> to
	 * introspect the relevent objects so that the right method can be called.
	 * Originally, <code>MethodUtils.invokeExactMethod</code> was used. This
	 * matches methods very strictly and so may not find a matching method when
	 * one exists. This is still the behaviour when exact matching is enabled.
	 * </p>
	 * 
	 * <p>
	 * When exact matching is disabled, <code>MethodUtils.invokeMethod</code> is
	 * used. This method finds more methods but is less precise when there are
	 * several methods with correct signatures. So, if you want to choose an
	 * exact signature you might need to enable this property.
	 * </p>
	 * 
	 * <p>
	 * The default setting is to disable exact matches.
	 * </p>
	 * 
	 * @return true iff exact matching is enabled
	 * @since Digester Release 1.1.1
	 */
	public boolean isExactMatch() {

		return useExactMatch;
	}

	/**
	 * <p>
	 * Set whether exact matching is enabled.
	 * </p>
	 * 
	 * <p>
	 * See {@link #isExactMatch()}.
	 * </p>
	 * 
	 * @param useExactMatch
	 *            should this rule use exact method matching
	 * @since Digester Release 1.1.1
	 */
	public void setExactMatch(boolean useExactMatch) {

		this.useExactMatch = useExactMatch;
	}

	/**
	 * Process the end of this element.
	 */
	public void end() throws Exception {

		// Identify the objects to be used
		Object child = digester.peek(0);
		Object parent = digester.peek(1);

		if (digester.log.isDebugEnabled()) {
			if (child == null) {
				digester.log.debug("[SetTopRule]{" + digester.match
						+ "} Call [NULL CHILD]." + methodName + "(" + parent
						+ ")");
			} else {
				digester.log.debug("[SetTopRule]{" + digester.match + "} Call "
						+ child.getClass().getName() + "." + methodName + "("
						+ parent + ")");
			}
		}

		// Call the specified method
		IntrospectionUtils.callMethod1(child, methodName, parent, paramType,
				digester.getClassLoader());

	}

	/**
	 * Render a printable version of this Rule.
	 */
	public String toString() {

		StringBuffer sb = new StringBuffer("SetTopRule[");
		sb.append("methodName=");
		sb.append(methodName);
		sb.append(", paramType=");
		sb.append(paramType);
		sb.append("]");
		return (sb.toString());

	}

}
